Certain embodiments of the present invention generally relate to conductive pads or contacts of electronic circuit cards, electrical cable assemblies, electrical components and the like, and more particularly to conductive pads that protect against electrical and electrostatic charge and build up on electrical elements that are mated with the conductive pads.
Various electronic systems, such as computers, comprise a wide array of components mounted on circuit boards, such as daughtercards and motherboards that are interconnected to transfer signals and power throughout the systems. Circuit cards having mating contacts are used to transfer signals and power between the circuit boards and other components of the systems. Various cable assemblies are used as well to transfer signals between components.
FIG. 1 is an isometric view of a conventional circuit card 10 housed in a connector to interconnect circuit boards and other components. The circuit card 10 includes a mating edge 12, a top edge 14 and a channel edge 16 defining a main body 17 therebetween. The circuit card 10 includes a plurality of conductive pads 18 (signal and ground conductive pads) arranged along the mating edge 12 of the main body 17. Conductive pads 22 (ground and signal pads) are arranged along the channel edge 16 of the main body 17. Traces 26 connect corresponding conductive pads 18 and 22. The traces 26 are staggered on opposite sides of the circuit card 10 and connected to corresponding conductive pads 18 and 22 through vias 20 and 24, respectively. The traces 26 may also be positioned to electrically connect two or more vias 20 or 24.
The channel edge 16 is received and retained within a channel of a connector housing (not shown). Typically, contact pins (not shown) engage the conductive pads 22 through cavities within the channels. Also, contacts (not shown) electrically connect conductive pads 18 on one circuit card 10 to conductive pads 18 on another circuit card 10.
Different types of circuit cards, which may be used in various applications, are known in the art. The circuit cards may be housed or retained in a wide variety of housings. The circuit card 10 is merely an example of a typical circuit card having conventional conductive pads 18 and 22. Typically, conductive pads 18 and 22, which may be used on circuit cards and on other electrical components, are single unitary conductive pieces directly connected to traces 26.
In order to establish electrical contact with the circuit card, a mating element of a corresponding circuit board or electrical component contacts the conductive pad. Often, electrostatic or other electrical energy builds up in the mating element. Often, an electrical charge may arc from the mating element to the circuit card. Also, when the mating element initially contacts the conductive pad, electrostatic energy built up on the mating element is discharged into the conductive pad. The electrostatic or electrical charge travels from the conductive pad through the electrical path emanating from the conductive pad. Typically, the electrical path leads to another component. The circuitry of the component, however, may not be able to handle the surge of electrostatic energy. Often, the electrostatic or electrical charge, or surge, may degrade or destroy the circuitry of components within an electrical system.
Thus, a need exists for a conductive pad that protects against the harmful effects of an electrostatic discharge.